The Newhall incident, also called the Newhall massacre, was a shoot out on April 5–6, 1970 in Newhall, Santa Clarita, California between two heavily armed criminals and four officers of the California Highway Patrol (CHP). In less than five minutes, the four CHP officers were killed in the deadliest day in California law enforcement history.[1]

At about 11:55 p.m. on April 5, CHP officers Walt Frago and Roger Gore conducted a traffic stop of Bobby Davis and Jack Twinning in conjunction with an incident reported to the CHP minutes earlier. Twinning and Davis initially cooperated with the officers but then opened fire, killing both of them. Moments later, officers George Alleyn and James Pence arrived on the scene and engaged Twinning and Davis in a shoot out. A bystander tried to help by firing an officer's weapon, but the three were out-gunned. Both Alleyn and Pence suffered fatal injuries, while the witness ran out of ammunition and took cover in a ditch. A third CHP patrol car arrived on scene, and the lone officer briefly exchanged gunfire with the perpetrators, who then fled.

Davis stole a car and attempted to flee the area, but he was spotted by police and arrested. Meanwhile, Twinning broke into a house, taking an occupant hostage. It was surrounded by deputies of the Los Angeles County Sheriff's Department, and Twinning released the hostage. He committed suicide around 9 a.m. as the deputies entered the house. Davis was convicted and sentenced to death for the murders. His sentence was commuted to life imprisonment without the possibility of parole in 1973; he killed himself at Kern Valley State Prison in 2009.

The Newhall incident resulted in a number of changes at the CHP, including procedural changes for arresting high-risk suspects, standardization of firearms, and firearms training used throughout the department.

https://en.wikipedia.org/wiki/Newhall_incident

Wikipedia wasn’t around 50 years ago.

...now I’m going to read your post :-)

Dammit. Post title fixed

When I went thru the academy 30 yrs ago they talked about it. We were given a photocopy of the photo of those four officers laid out in the morgue. I still have it stashed away somewhere, very sobering. I transported inmates from facility to facility for around 12 years, I took that job seriously.

Is this the one where the LE were putting their brass in their pocket before reloading?

All I can remember from that story was revolver and California.

ETA- or I could have just read the Wikipedia article...
In the aftermath of the Newhall shooting, although this was not based on the actions of any officer involved in the incident, the CHP modified their training to eliminate the practice of "pocketing brass" on the range (the act of picking up spent cartridge cases before reloading with fresh rounds). Several witnesses, including officers who responded to aid the four officers, said no brass casings were found in Officer Pence's clothing. One of the first responders, CHP Sergeant Harry Ingold (retired), said he found six brass cases on the ground next to the driver's door of Pence's and Alleyn's cruiser indicating that prior to being killed, Officer Pence had dumped his spent brass casings on the ground before reloading his revolver. This was confirmed by CHP Chief John Anderson in his book The Newhall Incident: America's Worst Cop Massacre

That was the Onion Fields

I remember the Motorola Training film about that from the academy.  I don't know how it why, but Tom Hayden was in just about all of those Motorola films.  Kind of odd for the ex-president of the SDS at Berkeley and Jane Fonda's husband.

Damn.  RIP officers.